body{
    text-align:center;
    background: url('../images/bg1.jpg');
    background-attachment:fixed;
    background-repeat:no-repeat;
    background-size:cover;
    -moz-background-size:cover;
    -webkit-background-size:cover;
}
.mylogin{
    position: absolute;
    width:400px;
    height:300px;
    left:50%;
    top:50%;
    background: #00688B;
    opacity:0.8;
    margin-left:-200px;
    margin-top:-150px;
}